Unit #1 Case Studies Diseases of The Central & Peripheral Nervous Systems ANATOMY & PHYSIOLOGY

The Nervous System The nervous system is the part of an animal’s body that coordinates voluntary and involuntary actions of the animal and transmits signals between the different parts of its body.

Central v. Peripheral Divisions Central (CNS) o Form: Brain, Spinal Cord, Optic Nerve o Form: Protected by bone and/or blood-brain barrier o Function: Integrates messages received from extremities, sensory organs and internal organs Peripheral (PNS):  Form: Nerves and Ganglia outside of CNS. Includes 10 of 12 cranial nerves  Form: Not protected by bone or blood- brain barrier  Function: Relays messages between CNS and extremities.

Autonomic v. Somatic Divisions of PNS Autonomic Divison (ANS) o Function: Involuntary control over heart rate, breathing, perspiration, salivation, pupillary dilation and digestion o Form: Afferent (sensory) & Efferent (motor) neurons o Subdivided in Sympathetic and Parasympathetic Divisions Somatic Division (SoNS)  Function: Voluntary control of body via efferent motor neurons  SoNS also encompasses reflex arcs, which do NOT travel to brain but instead rely on association neurons  Form: Comprised of three types of nerves  Spinal  Cranial  Association

Somatic Division (SoNS) The SoNS is responsible for controlling voluntary movements, using efferent (motor) neurons, and reflex arcs, using association (inter-) neurons. Three types of nerves: Spinal: Innervate much of the body, and connect through the spinal column to the spinal cord. (letter-number designations according to the vertebra through which they connect to the spinal column) Cranial: Innervate the head, and connect directly to the brain (especially the brainstem). (Roman Numerals descriptive names). Association: Connects other neurons (not “projection” neurons)

Somatic Reflex Arcs A reflex arc is a neural pathway that controls action reflexes (ex: patellar reaction) by synapsing in the spinal cord (not the brain). This allows for faster response time. Sensory information is still relayed to your brain, as the reflex action occurs.

Autonomic Division (ANS) The ANS is responsible for controlling involuntary movements, such as heart rate, breathing, perspiration, salivation, pupillary dilation, and digestion. It is composed of afferent (sensory) and efferent (motor) neurons. The ANS is further subdivided two divisions: The Sympathetic Division (“Fight or Flight”) The Parasympathetic Division (“Feed & Breed”)

Sympathetic and Parasympathetic Divisions of the ANS Sympathetic (Fight or Flight) Elevates blood pressure via vasoconstriction Increases respiratory volume via dilation of bronchioles Inhibition of peristalsis Dilation of pupil Parasympathetic (Feed & Breed) Decreased blood pressure via vasodilation Decreased respiratory rate Increased digestion, urination and defecation

Parasympathetic Shock?

Lower Sodium Conductance

Botox Protein derived from Clostridium botulinum bacteria Prevents the release of acetylcholine (ACH), the neurotransmitter than stimulates the contraction of skeletal muscle at the synapse By preventing contraction of the pretarsal, preseptal and orbital muscles of the face, glabellar lines do not form

Five Major Diseases of the CNS & PNS Amyolateral Sclerosis (ALS) Multiple Sclerosis (MS) Muscular Dystrophy (MD) Parkinson’s Disease (PD) Tay-Sachs Disease All show similar physical manifestations. All have very different causes and treatments